Roll cover for textile fiber drafting



Oct. 5,- 1948.

J. W. BAYMILLER ROLL COVER FOR TEXTILE FIBER DRAFTING Filed Feb. 27,1946 ZAP-REsIsTANTMomF/ED SYNTHETIC RUBBER INVENTOR John W Baym/WerPatented Oct. 5, 1948 ROLL COVER FOR TEXTILE FIBER DRAFTING John W.Baymiller, Manheim Township, Lancaster County, Pa., assignor toArmstrong Cork Company, Lancaster, Pa., a corporation of PennsylvaniaApplication February 27, 1946, Serial No. 650,609 19 Claims. (Cl.19-143) i Reference is had to the accompanying drawings, in which:

Figs. 1 and 2 are perspective views of roll covers in the form of cotsembodying my invention.

This application is a continuation-in-part of my copending applicationsSerial Nos. 542,880 and 542,881, both filled June 30, 1944, both nowabandoned. The invention relates to roll covers or cots for textilefiber drafting machinery used in the drafting of cotton, rayon, worstedand the like fibers. I have discovered that roll covers and cots made ofsynthetic rubber may be rendered lap-resistant by the incorporation inthe synthetic rubber of certain reaction products resulting from thedigestion in water disperson of a protein and a water-ionizablemodifying agent which combines with the protein to produce awater-soluble digestion product which is readily dispersible in thesynthetic rubber.

, The present invention is an improvement on the roll covers and cotsdescribed and claimed in my copending application Serial No. 634,230,which was a continuation-in-part of my copending applications SerialNos. 498,680, filed August 14, 1943; 526,380, filed March 14, 19M; and542,879, filed June 30, 1944, the last three applications being nowabandoned.

In the drafting of cotton, rayon, worsted and like fibers, it has beenfound that an unusual tendency exists for the fibers t6 lap up" aroundthe drafting roll, and the problem is particularly diificult in draftingrayon fibers. This problem exists in varying degrees with all types ofroll covers with which I am familiar and tends to reduce substantiallythe field of usefulness of roll covers.

Many attempts have been made to utilize various materials in theformation of roll covers for textile drafting machinery, such asspinning and drawing frames. Leather is a material frequently used. Itschief disadvantages reside in its cost, susceptibility to wear,prevalence of damage caused by the clearing of lap-ups from itscircumierence and the frequency with which replacements are necessary.Cork composition roll covers or cots have been used to a considerabledegree in the textile industry in place of leather. Their advantagesover leather reside in their initial low cost and the length of serviceeach cot is capable of rendering. These two types of cuts comprise thevast majority of cots used in the textile industry.

Attempts have been made to utilize oil-resistant synthetic rubbers toform the working surfaces of textile fiber drafting roll covers. Suchroll covers have been made of neoprene (a polymerized chloroprene) andPerbunan (a butadiene acrylonltrile copolymer), two well knownoil-resistant synthetic rubbers. These materials, while oil-resistant,do not possess the requisite resist-' ance to lapping up. Neoprene isnot used in the industry at the present time because of its extremetendency to lap up. Cots of Perbunan have been used to some extentforuse 'with cotton and in certain worsted operations,

since only a moderate amount of lapping up is encountered. Such cots arenot satisfactory for rayon fibers and certain cotton fibers, for theylap up excessively when used for drafting such fibers. In my copendingapplication Serial No. 634,230, referred to above, I disclosed that synthetic rubber roll covers which would be normally non-resistant tolapping up may be made resistant to lapping up under normal conditionsof use by the incorporation therein of an animal protein such as glue,together with certain in-' organic electrolytes or water-ionizableinorganic substances such as calcium nitrate, aluminum sulphate,potassium aluminum sulphate, sodium aluminum sulphate, ferric sulphate,potassium ferric sulphate, sodium ferric sulphate, sodium carbonate andphosphoric acid.

I have discovered that instead of adding the proteins and theelectrolytes as such to synthetic rubber as disclosed in my said priorapplication Serial No. 634,230, improved results may be secured bydigesting a protein with certain waterionizable modifying agents andincorporating the reaction product resulting from such digestion in thesynthetic rubber. I have found that greater lap resistance is attainedby the addition of the animal proteins and certain of the inorganicelecelectrolytes as such. I have also discovered that vegetable proteinsas well as animal proteins may be used in forming my digestion product,and that certain salts which are not effective when added as such withanimal proteins or alone are effective when reacted with protein to formmy digestion product. i

The reaction product which I incorporate into my synthetic rubber rollcovers is the product resulting from the digestion .in a waterdispersion,

preferably heated, of a protein and a waterbe avoided which have an 3ionizable modifying agent which combines with the protein to produce awater-soluble digestion product which is readily dispersible in thesynthetic rubber. ionizable in water and is believed to reduce theelectrokinetic potential at the cot surface to substantially zero, ashereinafter more specifically explained .under the theory.

' The preferred protein is the animal protein glue. Other animalproteins such as casein and be usedsuch for example as those derivedfrom soybeans and wheat. I believe that proteins as a class are suitablebecause proteins as a class may be reacted with the hereinafterdescribed modifying agents to produce a digestion product which isdispersible in the synthetic rubber. water-iomzable modifying agentswhich combine with the protein to produce a water-soluble diges- Thisdigestion product is readily gelatin may be used. Vegetable-proteins mayThe used, however, including calcium chloride, sodium nitrate, sodiumchloride, sodium sulphate, sodium phosphate and sodium carbonate, aswell as the corresponding potassium salts, zinc nitrate, zinc chloride,zinc sulphate, ferric and ferrous chlorides and stannic and stannouschlorides. The substances listed above are common industrial chemicalsand are readily obtainable. However, other water-soluble salts may beused which will combine with the protein to produce a watersolubledigestion product which is readily dispersible in the synthetic rubber.Certain salts produce a will not combine with the protein towater-soluble digestion product which is readily dispersible in thesynthetic rubber, such for example as .the alums, aluminum sulphate,potassium aluminum sulphate and sodium aluminum sulphate, because upondigestion they react with the glue to produce a hardened product whichis not water soluble and not readily dispersible in the syntheticrubber. However undigested mixtures of these'alums and glue may be usedas disclosed in my prior application Serial No. 634.230.

Non-oxidizing acids may be used to form the digestion product with theprotein, preferably phosphoric acid. Other non-oxidizing acids arehydrochloric, acetic, citric, tartaric, lactic and maleic. These acidsreact with the protein to produce a digestion product which is readilydispersible in the synthetic rubber. Acids should oxidizing effect uponthe glue or the synthetic rubber, such as nitric and sulphuric acids.

Bases may also be used to form the digestion product with protein,preferably ammonium hydroxide, which is particularly effective withvegetable proteins. Other bases may be used such as calcium hydroxide,which however is not particularly desirable because of its lowsolubility. v

In making my reaction product a water dispersion or solution is firstproduced by dispersing or dissolving the protein in water and dissolvingthe salt, acid or base, in water and mixing the two. The mixture of thewater dispersions or solutions of the protein and of the salt acid orbase is heated, preferably to a temperature o 5 parts of a 28% mixtureis stirred.

,The glue and water may be digestion product about 200 to 212 F. forapproximately 1% to 2 hours. A reaction occurs which produces adigestion product ,which is distinctly different from the mixture of theoriginal ingredients. For speed in the commercial production of mydigestion product, it is preferred to heat to a temperature at orslightly below the boiling point of water. However, the water solutionof the ingredients may be heated or warmed to a lower temperature, oreven reacted at room temperature, with a correspondingly longer periodof time required for digestion. In the case of ammonia, heating tends toevaporate ammonia and the heating should be adjusted to a point of asrapid reaction as can be attained without undue loss from evaporation.

The preferred digestion product ismade from glue and calcium nitrate byadding approximately 50 parts of animal glue (Rex glue) to 25 parts byweight of water. Parts are given as parts by weight throughout thisspecification. placed in a vessel over a water bath until theglue'melts. Twenty parts of dry calcium nitrate are dissolved in 20parts of water and the solution poured into the dispersionv of animalprotein and the mixture is stirred. The mixture is then permitted todigest for about 1 hours at a temperature of about 212 F. withoccasional stirring to produce a digestion or reaction product which isto be incorporated in the synthetic rubber mix.

, When vegetable protein is used, the preferred modifying agent isammonium hydroxide. Fifty parts of vegetable protein, such as soybean orwheat protein, are mixed with 50 parts of water and stirred to form awater dispersion. About aqueous solution of ammonia is poured into theprotein dispersion and the The mixture is thenallowed to digest at roomtemperature for about twentyfour hours with occasional stirring, toproduce a digestion or reaction product which is to be incorporated inthe synthetic rubber mix.

For convenience in description, I refer to the salts, acids and baseswhich react with the protein to form the digestion product as modifyingagents. The proportion of modifying agent to protein may be varied overfairly wide limits. The optimum proportion is about 20 parts ofmodifying agent to about 50 parts of protein. The preferred range isfrom about 10 to 30 parts of modifying agent to 50 parts of protein.Below such range the beneficial effect of the modifying agent becomesprogressively less, although appreciable benefit is observable down toabout 5 or even 2% parts of modifying agent to 50 parts of protein.While it is preferred not to exceed about'30 parts of modifying agent to50 parts of protein, the modifying agent may be somewhat increased, upto as high as about 40 parts of modifying agent to 5!) parts of protein,although the synthetic rubber.

The amount of digestion product to be incorporated in the syntheticrubber may vary over fairly wide limits.

to the synthetic rubber is about 70 parts of digestion product to partsof rubber. This proportion is figured on the dry weight of the proteinand modifying agent. It is in general undesirable to incorporate lessthan about 20 parts of the digestion product to 100 parts of thesynthetic rubber since not enough improvement in lap resistance is en-The optimum-proportion of countered with a-lesser amount. It ispreferred to use at least about 40 parts of digestion product to 100parts of synthetic rubber. The digestlon productmay be incorporatednearly to the point where itceases to be the internal phase. However, itis in general inadvisable to incorporate more than about 100 parts ofdigestion product to 100 parts of synthetic rubber. It is preferred thatthe digestion product be not more than about 80 parts to 100 parts ofthe synthetic rubber.

While in the neighborhood of 70 parts of digestion product to 100partsof synthetic rubber has been found to give excellent results withmost synthetic rubbers, the particular percentages may be variedsomewhat depending upon the particular synthetic rubber employed.Butadiene acrylonitrile copolymers are some.- what more resistant tolapping up than polymerized chloroprene and isoprene acrylonitrilecopolymers and therefore the amount of the digestion product requiredfor the butadiene acrylonitrile copolymers may be reduced somewhatbeyond that for polymerized chloroprene and isoprene acrylonitrilecopolymers.

By the term synthetic rubber I mean those synthetic substances which arecommonly referred to as synthetic rubbers and which have results wereobtained with a humidity differential existing. between desiccated airand air of 80% relative humidity at 70 F.:

Chemigum N-1"-2.2 10- grms. per sq. cm.

per day Perbunan-15x10 grms. persq. cm. perday Hycar OR-15-1.0 10-grins. per sq. cm. per

day

"Neoprene 'GN0.8 10- grms. per sq. cm. per

day

. plastic nature.

Reference is now made to the following examples in which the proportionsof the various ingredients are given by weight:

I II III IV V VI VII VIII IX X XI XII Hycar". 100 100 Chemigum" 100 100100 100 "Perbunan 100 100 100 100 Cork particles /30 mesh. l 50 50 50 50Digestion Product of 50 Parts Animal Glue and 20 Parts Calcium Nitratecalculated on dry weights 70 70 70 -70 70 70 Digestion Product of 50Parts Animal Glue and 20 Parts Phosphoric Acid calculated on dry weights70 70 70 l 70 70 70 ill l0 10 10 10 10 10 10 10 l0 l0 10 10 l5 15 15 1515 15 15 15 l5 15 15 l5 10 10 10 l0 1O 10 l0 l0 l0 1O 10 10 1.5 1.5 1.51.5 1.5 1.5 1.5 1.5 l.5 1.5 1.5 1.5 0.3 0.3 (.3 0.3 0.3 0.3 0.3 0.3 0.30.3 0.3 0.3 Zinc oxide 5 5 5 5 5 5 5 5 5 5 5 5 physical propertiesresembling those of natural rubber, as set forth, for example, in thedefinition of synthetic rubber appearing on pages 3 to 4 of the circularC427 of the United States Department of Commerce entitled Syntheticrubber: A Review of Their Compositions, Properties, and Uses, byLawrence A. Wood, issued June 25, 1940; and on page 9 of Natural' andSynthetic Rubbers, by Harry L. Fisher, being the Edgar Marburg lecturesof 1941 presented before the forty- In place of the digestion productsformed from glue and a salt and glue and an acid, the digestion productin the same amount formed by digesting a protein, either a vegetable oran animal protein with ammonium hydroxide, may be used.

In the above compounds, Hycar, Chemigum, and Perbunan are syntheticrubbers of fourth annual meeting of the American Society for TestingMaterials.

My tests have been carried out primarily with synthetic rubbers of thefollowing types: butadiene acrylonitrile copolymers, of which Perbunan,Chemigum and Hycar are commercial examples, and which contain varyingpercentages of acrylonitrile; chloroprene polymer, of which neoprene isa commercial example; and isoprene acrylonitrile copolymers, which havebeen made experimentally. These have all proved satisfactory syntheticrubber bases for lap-resistant cots when mixed with my digestionproduct. These synthetic rubbers have certain common characteristicswhich adapt them for use in covers for textile drafting rolls. They arevulcanizable. When vulcanized they are oil-resistant, resilient andnon-thermoplastic. When vulcanized they are all water permeable to acertain extent, as indicated by the following tests, the results ofwhich are expressed in the terms used by the American Society forTesting Materials in Methods for Water Vapor Permeability, in which thethe acrylonitrile butadiene copolymer type containing about 40%, 30% and26% respectively of acrylonitrile. The cork particles are included inthe composition to aid in resistance to eyebrowing. In the specificexamples the glue was Cudahy Packing Companys Rex glue, although othercommercial glues may be employed, such I as Swifts"Econ-omy glue, PeterCooper AA glue, etc.

Sulfur, of course, is the vulcanizing agent; titanium dioxide and carbonblack areus'ed primarily as pigments. If desired, other pigments andfillers maybe included in the above compositions. Triacetin is used as asoftener or plasticizer and other plasticizers may be used in its place,for example, tricresyl phosphate or dibutyl phthalate or dibenzyl ether.Benzothiazyl disulfide (Altax) is a conventional accelerator and, ofcourse, other accelerators may be used with satisfactory results. "Zincoxide is used primarily as an activator for the accelerator.

The synthetic rubber is milled on any suitable rubber mill until it issatisfactory for use, then my digestion product is milled into therubber at a suitable temperature. In milling my digestion product intothe synthetic rubber, it is desirable that the digestion product bemilled into the rubber on a warm mill. The mill should be warm but mustnot be too hot for if it to be too hot, the water may evaporate from thedigestion product prematurely so that the digestion product may adhereto the rolls of the rubber mill. After the digestion product has beenthoroughly dispersed in the synthetic rubber mix the milling iscontinued, preferably 'with heat applied to the mill rolls until thewater contained in the digestion product has been largely driven off.The digestion product is readily dispersible in the synthetic rubber andis used in an amount to form the dispersed or internal phase. When thedigestion product has been thoroughly milled into the synthetic rubberit is uniformly dispersed therein so that the mixture has the appearanceof a homogeneous solution. When a thin sheet of the milled rubber isviewed in frontof a light it has nearly the same transparent appearanceas the untreated synthetic rubber. There are no discrete particles ofthe digestion product observable to the naked eye or even under 150magnifications. The remaining ingredients should be added to the massafter the digestion product has been uniformly dispersed throughout therubber. They may be added to the milled mass as is customary andwell-known in the industry.

The synthetic rubber compound so prepared is then sheeted or tubed bymeans of any suitable tubing device. If the compound be sheeted, it isrolled about a mandrel to form a cot. If the compound be tubed, the tubeis slipped on the.

mandrel. In either case, the cot stock disposed about the mandrel iswrapped with wet fabric tape and cured with open steam. The temperatureand duration of the cure may be varied in accordance with standardvulcanizing practice. For the above compounds, a curing time of 55minutes at 300 F. is generally satisfactory.

After the curing operation the tubes are removed from the mandrel, thefabric tape is removed, and the tubes are buffed or ground to obtain asatisfactory surface, are cut to size to form cots, and bevelled, ifdesired. Cots so formed may be supplied to spinning mills or, ifdesired, may be mounted on spinning rolls at the place of manufacture.

It appears that the capacity of my digestion product to absorb water isconsiderably increased over that of the protein alone. One advantagemany materials which are not sufliciently compatible with rubber to bemilled therein and dispersed satisfactorily through the synthetic rubbermay be digested with the protein and the digestion product so formed iseasily and readily milled into the rubber. For example, calcium chlorideis not satisfactory for decreasing the lap resistance of a syntheticroll cover when incorporated alone or as an undigested mixture withanimal glue, but is found to be a highly satisfactory salt for use whendigested with protein as above described. Other materials which areunsatisfactory if used alone or in an unreacted mixture with animalprotein are sodium chloride, sodium nitrate, trisodium phosphate, citricacid, lactic acid, tartaric acid and maleic acid. These materials,however, are very satisfactory modifying agents for digestion withproteins.

My digestion products-are compatible with the synthetic rubber in whichthey are incorporated and do not deleteriously affect the syntheticrubber mix.

of my digestion product resides in the fact that Suitable compoundsembodying polymerized chloroprene are as follows:

XIII XIV XV XVI "Neoprene GN". 100 100 100 Cork particles 2/30 mesh 4242 Digestion Product of 50 Parts Anim Glue and 20 Parts Calcium Nitratecalculated on dr; weights 70 70 Digestion Product of 60 arts Animal Glueand 3) Parts Phosphoric Acid calculated on dry weights 70 70 Light manesia 4 4 4 4 Stearic ac d 3 3 3 3 Titanium dioxide l5 15 l6 l6Graphite... 2. 6 2. 6 2. 6 2. 6 Neozone A. 2 2 2 2 Zinc oxide. 6 5 6 5In place of the digestion products formed from glue and a salt and glueand an acid, the digestion product in the same amount formed bydigesting a protein, either a vegetable or an animal protein withammonium hydroxide, may be used,

These materials may be compounded in the samemanner as described withregard to acrylo- XVII XVIII XIX XX Isoprene acrylonitrile cogolymer.100 100 100 100 Cork particles 20/30 mes 50 50 D gestlou Product of 50Parts Anunal Inc and 20 Parts Calcium Nitrate calculated on dry weight70 70 Digestion Product of 50 Parts Animal Glue and 20 Parts PhosphoricAcid calculated on dry weight 70 70 Titanium dioxide l5 15 15 15Triacetin 10 10 10 10 Carbon Black 0.3 0.3 0. 3 0. 3 ulfur 10 l0 l0 l0Benzothiazyl disulfide 2 2 2 2 In place of the digestion products formedfrom glue and a salt and glue and an acid, the digestion product in thesame amount formed by digesting a protein, either a vegetable or ananimal protein, with ammonium hydroxide'may be used.

Cork granules may be included in any of these various synthetic rubbermixes. The presence of the cork granules improves the "eyebrowresistance, particularly of cots of the chloroprene type.

An eyebrow" may be defined as a collection of waste fibersdpulled fromthe roving by the cot which is not carried rearwardly of the clearerboard by the rotating cot and which accumulate at the front of theclearer board in a bunch-like formation. As the eyebrow increases insize, it is occasionally pulled from the clearer board by the rovingbeen spun and causes a hard spot in the yarn which is called a nub.

The cork granules may be included in various quantities. I have foundthat the amount of cork granules included in the various mixes may fallwithin the range of 25 to parts to each 100 parts of the syntheticrubber mix. The cork granules may vary as to particle size. For mostsatisfactory results the cork granules should not be larger than about10 mesh or smaller than about 50 mesh and I have found that particularlygood results are obtained with cork granules falling withinthe range of20 to 30 meshes to the inch United States Standard sieves. The corkgranules are preferably added along with the other ingredients which areincorporated in the synthetic rubber on the rubber mill and are thusuniformly distributed in the synthetic rubber mix so that there is auniform distribution of such particles I cots as heretofore producedwithout being modified by an effective amount of a water-ionizableelectrolyte may be explained as follows: Acertain amount of water isadsorbed upon the surface of a cot, particularly under the operatingconditions of modern textile mills where a relatively high humidity,usually about 60%, is maintained to prevent accumulation of staticcharges and to render the fibers more amenable to drafting. I believethat such water forms a Helmholtz electric double layer upon the surfaceof the cot and, inthecase of synthetic rubber compounds, the rubbersurface has an electrokinetic or zeta potential negative with respect tothe moisture film. Such electrokenitic or zeta potential is described inElectrokinetic Phenomena, Abramson, 1934; Outlines of Biochemistry,Gortner, second edition, 1938, pages 147-150; Physical Chemistry,MacDougall, revised edition, 1943, pages 686694.

The fibers also have a certain amount of water adsorbed on theirsurfaces so that I believethat there is present on the fibers also aHelmholtz double layer with the surface of the fiber having a zetapotential negative with respect to the adsorbed water film. There isthus a zeta potential set up in the cot-water interface and another zetapotential set up at the fiber-water interface resulting in firm adhesionof water to both the synthetic rubber and fiber. When the two arepressed firmly together, as in the drawing operation, the water filmbecomes common to both the cot and the fiber and the forces of cohesionin the water itself tend to bond or cement together the cot and fiber,thus causing lapping of the fiber around the cot. I believe that thistheory acceptablyexplains the lapping up action which occurs with theusual synthetic rubber cots of commerce. While I believe that theelectrokinetic theory offers the best explanation of the phenomena whichI have observed, it is to be understood that the invention is not be belimited to the theory.

- I believe that the non-lapping characteristics imparted to syntheticrubber cots by the incorporation of my water-ionizable digestion productis carried out wherein synthetic rubber cots containing my digestionproduct have been prepared under extremely dry conditions, that is, theyhave been dried on the rubber mill-at a high tempera-" moisture isrequired to bring the electrolytic digestion product into water solutionwhere its charges are effective in reducing the zeta potential.

I have further found that while some moisture is required to make thesynthetic rubber cots described in this application effectivelynon-lapping. the amount of moisture thus required is substantially lessthan that required for rendering nonlapping the cots described in myearlier copend- 'ing application Serial No. 634,230, and that thenon-lapping characteristics ofthe cots disclosed Y in this applicationare enhanced over those disdue to the fact that the digestion product inthe I synthetic rubber-electrolyte mixture supplies the necessaryelectric charges to reduce the zeta potential at the cot-water interfaceor the fiberwater interface to zero or substantially zero, therebydestroying the adhesion between the cot and the fibers and thuspreventing lapping. The zeta orelectrokinetic potential theory is setforth in greater detail in my copending application SerialNo. 634,230,to which reference is made.

I have also found that moisture should be I present'at the surface ofthe cot, at least to the extent normally present under operatingconditious in textile mills. Experimentshave been closed in my saidprior application at the same relative humidities.

I have also found that the effectiveness of my digestion product insynthetic rubber cots where moisture is present is related to the watervapor permeability of the vulcanized'synthetic rubber.

Forinstance, "Chemigum N-l has the highest water vapor permeability ofthe synthetic rubbers with which I have experimented. Perbunan" has thenext highest permeability and is followed by Hycar 0R-15, neoprene GNand a special isoprene acrylonitrlle copolymer, which is madeexperimentally, in the order named. I have found that the higher thepermeabilityof the synthetic rubber containing my electrolytic digestionprod-. uct, the better the resistance to lapping; I offer as a possibletheoretical explanation of these observations that the electrolyticdigestion product incorporated into the synthetic rubber is more readilyavailable at the surface in the case of the synthetic rubber having thegreater water vapor permeability.

In the drawings, Fig. 1 is a perspective view of a roll cover embodyingr v invention; and Fig. 2 is a similar view of such roll cover includingcork granules.

While I have disclosed certain preferred embodiments of my invention, itwill be understood that my invention is not limited thereto but may beotherwise embodied and practiced within the scope of the followingclaims.

I claim: a

1. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a vulcanized oil-resistant resilientnon-thermoplastic somewhat water vapor permeable synthetic rub- 11drafting having a working surface made of a vulcanized oil-resistantresilient non-thermoplastic somewhat water vapor permeable syntheticrubber which is normally non-resistant to lapping up, having uniformlydispersed therein as the dispersed phase from 20 to 100 parts per '100parts of the synthetic rubber of the reaction product resulting from thedigestion in water dispersion of a protein and-from to 40 parts per 50parts of protein of a water-ionizable salt which does not deleteriouslyaflect the protein or the synthetic rubber and combines with the proteinto produce a compatible water-soluble digestion product which is readilydispersible in the synthetic rubber whereby the roll cover is renderedlap-resistant.

3. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a vulcanized oil-resistant resilientnon-thermoplastic somewhat water vapor permeable synthetic rubber whichis normally non-resistant to lapping up, having uniformly dispersedtherein as the dispersed phase from 20 to 100 parts per 100 parts of aprotein and-from 5 to 40 parts per 50 parts of protein of awater-ionizable non-oxidizing acid which does not deleteriously affectthe protein or the synthetic rubber and combines with the protein toproduce a compatible water-soluble digestion product which is readilydispersible in the synthetic rubber, whereby the roll cover is renderedlap-resistant.

4. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a vulcanized oil-resistant resilientnon-thermoplastic somewhat water vapor permeable synthetic nitrate per'50 parts of protein, whereby the roll cover is rendered lap-resistant.

7. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a vulcanized oil-resistant resilientnon-thermoplastic somewhat water vapor permeable synthetic rubber whichis normally non-resistant to lapping up, having uniformly dispersedtherein phosphoricacid per 50 parts of protein, whereby the'roll' coveris rendered lap-resistant.

8. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a dispersion of a protein and from 5 to 40 partsof ammonium hydroxide per 50 parts of protein,

whereby the roll cover is rendered lap-resistant.

thetic rubber, whereby the roll cover is rendered A lap-resistant.

5. A lap-resistant rollcover for textile fiber drafting having a workingsurface made of a vulcanized oil-resistant resilient non-thermoplasticsomewhat water vapor permeable synthetic rubber which is normallynon-resistant to lapping up, having uniformly dispersed therein as thedispersed phase an-eifective amount of the heat reaction productresulting from the digestion in a heated water dispersion of a proteinand a water-ionizable modifying agent which does not deleteriouslyaffect the protein or the synthetic rubber and combines with the proteinto produce a compatible Water-soluble digestion product which is readilydisperslble'in the synthetic rubber, whereby the roll is renderedlap-resistant.

6. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a vulcanized oil-resistant resilientnon-thermoplastic somewhat-water vapor permeable synthetic rubber whichis normally non-resistant to lapping up, having uniformly dispersedtherein as the dispersed phase from 20 t'o 100 parts per 100 parts ofthe synthetic rubber of the reaction product resulting from thedigestion in water dispersion of a protein and from 5 to 40 parts ofcalcium 9. A lap-resistant roll cover for textile fiber drafting havinga working surface made of a vulcanized oil-resistant resilientnon-thermoplastic somewhat water vapor permeable synthetic rubber whichis normally non-resistant to lapping up, having uniformly dispersedtherein in an amount between 20 and 100 parts per 100 parts of thesynthetic rubber of the reaction product withthe protein to produce acompatible watersoluble digestion product which is readily dispersiblein the synthetic rubber, whereby the roll cover is renderedlap-resistant.

10. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a vulcanized oil-resistant resilientnon-thermoplastic somewhat water vapor permeable synthetic rubber whichis normally non-resistant to lapping up, having uniformly dispersedtherein as the dispersed phase from about 40 to about parts per parts ofthe synthetic rubber of the reaction products resulting from thedigestion in water dispersion of a protein and from 10 to 30 parts per50 parts of protein of a water-ionizable modi fying ag'entfwhich doesnot deleteriously aifect the protein or the synthetic rubber andcombines with the protein to produce a compatible watersoluble digestionproduct which is readily dispersible in the synthetic rubber, wherebythe roll cover is rendered lap-resistant.

11. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a synthetic rubber selected from the classconsisting of rubber-like butadiene acrylonitrile copolymers,polymerized chloroprene and isoprene acrylonitrile copolymers, havinguniformly dispersed therein as the dispersed phase an effective amountof the reaction product resulting from the digestion in water dispersionof a protein and the synthetic rubber and thetic rubber, whereby theroll cover is rendered lap-resistant.

12. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a rubfber-like butadiene acrylonitrile copolymerhavwhich does not deleteriously affect the protein or combines with theprotein to produce a compatible water-soluble digestion product which isreadily dispersible in the synthetic rubber, whereby the roll cover isrendered lap-resistant.

13. A lap-resistant roll cover for textile fiber drafting having aworking surface made of a vulcanized oil-resistant resilientnon-thermoplastic somewhat water vapor permeable synthetic rubber whichis normally non-resistant to lapping up, having uniformly dispersedtherein as the dispersed phase an effective amount of the reactionproduct resulting from the digestion in water dispersion of glue and awater-ionizable modifying agent which does not deleteriously affect theprotein or the synthetic rubber and combines with the glue to produce'acompatible water-soluble digestion product which is readily dispersiblein the synthetic rubber, whereby the roll cover is renderedlap-resistant.

14. A lap-resistant roll cover for textile fiber drafting in accordancewith claim 1, having cork granules uniformly distributed in thesynthetic rubber mix at the working surface.

1-5. A lap-resistant roll, cover for textile :iiber drafting inaccordance with claim 1, having particles Of a material which minimizeseyebrowing uniformly distributed in the synthetic rubber mix at theworking surface.

16. A lap-resistant roll cover for textile fiber drafting having 'aworking surface made of a rubber-like butadiene acrylonitrile copolymerhaving uniformly dispersed therein as the dispersed phase from 40 to 80parts per 100 parts of the synthetic rubber of the reaction productresulting from the digestion in a heated water disperthe digestion inwater dispersion of a protein and a water-ionizable modifyi a ent 'ofthe synthetic resulting from the digestion in a water dispersion -ofglue and from 5 to 40 parts per 50 parts of sion of glue and from 10 to30 parts of calcium nitrate per 50 parts of glue, whereby the roll coveris rendered lap-resistant.

1'1. A lap-resistant roll, cover for textile fiber drafting having aworking surface made of a vulcanized oil-resistant resilientnonthermoplastic somewhat water vapor permeable synthetic rubber whichis normally nonresistant to lapping up,

having uniformily dispersed therein as the dis- 20 to 100 parts per 100parts;

persed phase from rubber of the reaction product glue of awater-ionizable modifying agent which does not deleteriously affect theglue or the synthetic rubber and combines with the glue to produce acompatible water-soluble digestion product which is readily dispersiblein the synthetic rubber, whereby the roll cover is rendered lap-resis-'tant.

18. A lap-resistant roll cover for textile fiber drafting in accordancewith claim 9, having cork granules uniformly distributed in thesynthetic rubber mix at the working surface;

19. A lapresistant roll cover for textile fiber drafting in accordancewith claim 9, having particles of a material which minimizes eyebrowinguniformly distributed in the synthetic rubber mix at the workingsurface.

JOHN W. BAYMILLER.

REFERENCES CITED The following references are of record in the.

filo of this patent:

UNITED STATES PATENTS Number Name Date' 1,988,491 Hazell Jan. 22, 19352,010,012 Collins Aug. 6, 1935 2,012,223 Cutler Aug. 20, 1935 2,304,656Rockoif Dec. 8, 1942 FOREIGN PATENTS Number Country Date Great Britain1898 Certificate of Correction Patent No. 2,450,410. October 5, 1948.

JOHN W. BAYMILLER It is hereby certified that errors appear in theprinted specification of the above numbered patent requiring correctionas follows:

Column 1, line 7, for the word filled read filed; column 2, line 29,after such to insert the; column 7, line 3, after if it strike out to;column 8, line 65, for been read being; column 9, line 31, forelectrokenitic read electrok'inet'ic; line 51, after cot and insert the;line 58, for not be read not to; column 11, line 65, claim 5, after rollinsert cover; column 12, line 53, claim 10, for products read product;and that the said Letters Patent should be read with these correctionstherein that the same may conform to the record of the case in thePatent Oflice.

Signed and sealed this 15th day of March, A. D. 1949.

THOMAS F. MURPHY,

Assistant G'ommz'asioner of Patents.

